In 12th-century Palestine, Barbara is kidnapped by the evil Emir El Akir
while Ian is knighted for helping save the life of King Richard. The
Doctor and Vicki are entangled in Richard's attempts to force his sister
Joanna to marry Saphadin, brother of the Saracen leader Saladin, in order
to bring an end to the Crusade. Ian, meanwhile, sets out in search of
their lost companion.

Production

David Whitaker formally ended his tenure as Doctor Who's story
editor on October 31st, 1964. During the transition period while he was
being trailed by his successor, Dennis Spooner, Whitaker had written one
adventure, The Rescue, to help introduce new
companion Vicki. On November 1st, with Whitaker now having officially left
the production team, Spooner took the opportunity to commission him again,
this time for an historical called “The Saracen Hordes”
(“The Lionheart” may also have been considered as a
title).

In developing his storyline, Whitaker was particularly inspired by two
events which occurred in the autumn of 1191. The first was an attempt, in
October of that year, by King Richard I to arrange the marriage of his
widowed sister, Joanna, to al-Adil Saif-ed-Din (known to the Europeans as
“Saphadin”), the brother of Muslim ruler Salah al-Din
al-Ayyubi (known as “Saladin”). Whitaker also made use of a
late November incident in which a hunting party led by Richard was waylaid
by Saracens outside Jaffa; Richard was spared captivity when William de
Preux convinced the attackers that he was actually the King.

William Hartnell objected to dialogue which implied an
incestuous relationship between Richard and Joanna

The director assigned to Serial P was Douglas Camfield, who had impressed
producer Verity Lambert when he helmed the fourth episode of Planet Of Giants (which was eventually edited
down to form half of the third televised episode) toward the end of the
previous recording block. Camfield and Spooner were both very pleased with
Whitaker's scripts, and in particular his dialogue. Less content,
apparently, was William Hartnell, who felt that some dialogue implying an
incestuous relationship between Richard and Joanna was inappropriate in
Doctor Who. The offending material was removed.

Three days of filming at the Ealing Television Film Studios began on
February 16th. Whitaker's storyline had been structured to minimise Ian's
involvement in the third episode, allowing William Russell to take a
week's holiday; his only scene in that installment was prerecorded at this
time. Russell was also scheduled to film the scene where an army of ants
crawls up Ian's arm. Russell refused to participate in this shot, and
production assistant Viktors Ritelis agreed to double for him.

By the time studio recording began on March 5th, the serial had been
renamed The Crusade; as usual, each episode would be taped on
consecutive Fridays in Riverside Studio 1. Amongst those considered for
the part of Richard was Nicholas Courtney, who would later play the
recurring role of Brigadier Lethbridge-Stewart; for this story, however,
Courtney lost out to Julian Glover. Joanna was portrayed by Jean Marsh,
whose first husband had been Jon Pertwee (later to play the Third Doctor);
Marsh herself would imminently be cast as short-lived companion Sara
Kingdom. Also in the running for the role of Joanna was Adrienne Hill, who
would soon play Katarina, another companion with a brief tenure on
Doctor Who. It was on March 19th -- the day that The Wheel Of
Fortune was taped -- that Maureen O'Brien was issued a new contract
for this serial and the next two in production. This replaced the
extension of January 28th, likely because O'Brien had been granted a
raise.

It was around the time that The Crusade was in production that
Lambert decided she would leave Doctor Who at the end of the
current recording block. With Whitaker and associate producer Mervyn
Pinfield having already moved on, this meant that all of the original
production triumvirate would have departed from Doctor Who.